Rather, Earnest and Wong say they believe the answer is right here in Solana Beach, where they opened the doors of Grrreen, their plug-in hybrid company, late last year.

In just a few short months, they have already converted the poster child for excessive greenhouse gas emissions, the Ford F150, into an energy-conserving, Earth-loving machine. They've done the same to a Toyota Tacoma, and up next, a Hummer.

"We've proved the concept. Now the trick is execution," Earnest said. "Can we deliver converter kits cheaper than anyone else can? I think we can pull it off."

The converter kit includes an electric motor, a small controller box and batteries. The kit can be installed in a typical mechanic's garage and does nottouch any existing components that would void the manufacturer's warranty, he said.

The electric motor would typically be used for the first 35 miles per hour, and then the controller box would switch seamlessly to the gas engine for higher speeds, maximizing efficiency for both power sources, he explained.

More than 50 percent of the time a typical driver is traveling 35 miles per hour or slower, which translates into upwards of 50 percent gas savings for plug-in hybrids, Wong said.

Also, the amount of carbon put into the atmosphere could be reduced significantly, not to mention dependence on foreign oil.

Grrreen is initially focusing on converting government and municipal fleets. Local cities and counties are interested in the opportunity because state mandates to reduce greenhouse gas emissions beginning in 2012 are fast approaching, they said.

Right now, a converter kit costs more than $10,000, a price that varies based on the size of the motor and type of batteries. However, Earnest said he is hoping to bring the price well below that to compete with the premium to purchase a new hybrid versus a regular vehicle.

The investment pays for itself in a few years in gas savings as well as extending the life of the vehicle by reducing wear and tear on the gas engine, Earnest said.

Electric cars have been in development since the 1970s, but have not been embraced until now.

Wong knows. He worked with electric car guru Andy Frank, a professor at University of California, Davis, pitching plug-in hybrids to numerous manufacturers 10 years ago.

"Gas was too cheap, no one paid attention," Wong said. "If Hummer would have listened to Prof. Andy Frank, they would still be in business today."

Americans are still skittish about all-electric, Earnest said, in part because they are afraid they will run out of juice before they get home, to work or to a charging station.

The plug-in hybrid helps bridge that gap, and the Grrreen converter kit speeds up the process by converting existing vehicles long before new plug-in hybrids will be widely available, they noted.

While it seems the time is ripe for plug-in hybrid, Wong said he is not going to be satisfied until at least one million conversion kits are out on the road.

"It's not going to make a difference until we get into the tens of millions," he said.